English

The period-index problem for hyperk\"ahler manifolds

Algebraic Geometry 2025-01-06 v2

Abstract

We conjecture that every unramified Brauer class αBr(X)\alpha\in \text{Br}(X) on a projective hyperk\"ahler manifold XX satisfies ind(α)per(α)dim(X)/2\text{ind}(\alpha)\mid\text{per}(\alpha)^{\dim(X)/2}. We provide evidence for this conjecture by proving it for two large classes of projective hyperk\"ahler manifolds: For projective hyperk\"ahler manifolds admitting a Lagrangian fibration and for Hilbert schemes of K3 surfaces.

Cite

@article{arxiv.2411.17604,
  title  = {The period-index problem for hyperk\"ahler manifolds},
  author = {Daniel Huybrechts},
  journal= {arXiv preprint arXiv:2411.17604},
  year   = {2025}
}

Comments

37 pages. Minor corrections

R2 v1 2026-06-28T20:13:25.467Z